[PATCH GCC8][28/33]Don't count non-interger PHIs for register pressure

[Bin.Cheng]

On Wed, Apr 26, 2017 at 2:32 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Tue, Apr 18, 2017 at 12:52 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
>> Hi,
>> Given only integer variables are meaningful for register pressure estimation in IVOPTs,
>> this patch skips non-integer type PHIs when counting register pressure.
>> Is it OK?
>
> Huh.  I suppose it only makes a difference because you are ignoring
> POINTER_TYPE_P
> IVs?  At least I would be surprised if get_iv returns true for float
> or vector PHIs (yeah, see
> early out in get_iv)?  So why exclude POINTER_TYPE_P IVs?
Hmm, but if get_iv returns non-NULL, the phi won't be counted because
loop is continued?  Actually, all IV and invariants are skipped by
checking get_iv, so this is only to skip floating point phis.

Thanks,
bin
>
> Richard.
>
>> Thanks,
>> bin
>>
>> 2017-04-11  Bin Cheng  <bin.cheng@arm.com>
>>
>>         * tree-ssa-loop-ivopts.c (determine_set_costs): Skip non-interger
>>         when counting register pressure.
>>